Abstract
Since plant extracts have long been known to be chitin inhibitor and agents for developmental arrest, chitinase genes and genes that are vital for starting the differentiation program of cells at discrete steps during development are major targets for biocide plant extracts. The current study evaluates the in vitro toxic effects of golden piller (Cupressus macrocarpa) and galangal (Alpinia officinarum) against Spodoptera frugiperda Sf9 cell line. Also, changes in gene expression levels of chitinase genes (SFch-1, SFch-2) and fibroblast growth factor receptor gene (SFbt1) were demonstrated. Cell sensitivity assay (MTT) showed that golden piller was more toxic than galangal in cell viability tests and more potent in the cell growth inhibition. The calculated LC50 were 120 mu M and 200 mu M for golden piller and galangal, respectively. Both plant extracts significantly reduced the gene expression levels of chitinase genes and SFbt1 (p<0.05) following 72h of exposure to LC50. This work provides evidence of a viable use of these botanical extracts for pest control as well as highlight the mode of action during the process of chitin formation, degradation and cell proliferation.